1. Field of the Invention
The present invention generally relates to a stacked package device, and more particularly to a bottom package of a stacked package device including an interposer.
2. Description of the Related Art
Currently, a package-on-package (hereinafter referred to as POP) device is related to a semiconductor package disposed on another semiconductor package. The basic object of the POP device is to increase the density of components so as to result in more functions of components per unit volume and better regional efficiency. Thus, the total area of the POP device can be decreased, and the cost is reduced simultaneously.
FIG. 1 is a diagrammatic sketch in a sectional view illustrating the structure of an example of a conventional stacked package (i.e. package-on-package, POP) device 50, i.e. a two-stack multi-package module (MPM), in which the interconnection is made by solder balls 28. In this POP device 50, a first package is the “top” package 20, and a second package is the “bottom” package 10. The top package 20 is stacked on the bottom package 10. The top package 20 includes a chip 24 attached onto the substrate 22. The substrate 22 of the top package 20 has upper and lower metal layers patterned to provide appropriate circuitry and connected by way of vias. The chip 24 is attached on an upper surface of the substrate 22 by using an adhesive 23, e.g. die attach epoxy. The bottom package 10 includes a chip 14 attached onto a substrate 12. The substrate 12 of the bottom package 10 also has upper and lower metal layers patterned to provide appropriate circuitry and connected by way of vias. The chip 14 is attached on an upper surface of the substrate 12 by using an adhesive 13, e.g. die attach epoxy.
In the top and bottom packages 20, 10, the chips 24, 14 are respectively bonded to wire bond sites 25, 15 on the upper metal layer of the substrate 22, 12 by means of bonding wires 26, 16, so as to establish electrical connections. The chips 24, 14 and the bonding wires 26, 16 are respectively encapsulated with top and bottom molding compound 27, 17. Solder balls 28 are mounted onto bonding pads located on the peripheral margin of a lower surface of the substrate 22 to provide interconnection to the bottom package 10. Solder balls 18 are mounted onto bonding pads located on a lower surface of the substrate 12 to provide electrical connection to an external circuit board (not shown).
The interconnection between the top and bottom packages 20, 10 of the POP device 50 is achieved by reflowing the solder balls 28 attached to the bonding pads located on the peripheral margin of the lower surface of the substrate 22 of the top package 20 and attached to the bonding pads located on the peripheral margin of the upper surface of the substrate 12 of the bottom package 10.
However, the conventional POP device has not any interposer or substrate which is disposed between the top and bottom packages 20, 10 for providing the electrical connection or more functions.
Accordingly, there exists a need for a stacked package device capable of solving the above-mentioned problems.